Effects of various media compositions on the in- vitro germination and discoloration of immature embryos of bird of paradise (Strelitzia reginae)

Abstract

The optimal media composition for the in vitro germination of isolated Strelitzia reginae embryos was investigated. Different media treatments were compared to determine the effects of MS medium strength, activated charcoal (AC) and vitamin supplementation on the germination and seedling development of immature Strelitzia embryos. Results indicate the positive role of AC in reducing oxidative browning. The addition of AC (0.2 gl-¹)to the culture medium significantly reduced the discoloration of embryo explants and the culture media. Similarly, the addition of the vitamins (100 mgl-¹ Inositol, 0.1 mgl-¹ Thiamine, 0.1 mgl-¹ Pyridoxine, 2 mgl-¹ Glycine) resulted in a significant reduction in embryo discoloration. Furthermore, the addition of vitamins significantly increased root formation. Interactions between these media components resulted in significant effects. In treatments of half-strength MS with vitamin supplementation, both embryo and media discoloration were reduced. Interactions between vitamin and AC treatments presented a reduction in the embryo discoloration rate and an increased length of shoots, only when AC was absent in the media. When AC was added to vitamin supplemented media, the beneficial effects of vitamins were cancelled. The highest germination rate of embryos was observed in media containing AC without vitamin supplementation. A significant decrease in germination resulted with the addition of vitamins. The highest level of media discoloration was observed in half-strength MS media without activated charcoal and vitamin supplementation. Whilst the most effective media were; (half-strength MS without vitamins and with AC) or (half-srength MS with vitamins and without AC).